U.S. patent number 3,937,252 [Application Number 05/528,624] was granted by the patent office on 1976-02-10 for impulse signal producing device of the pneumatic pressure type.
This patent grant is currently assigned to Mikuni Kogyo Co., Ltd.. Invention is credited to Takashi Ishida.
United States Patent |
3,937,252 |
Ishida |
February 10, 1976 |
**Please see images for:
( Certificate of Correction ) ** |
Impulse signal producing device of the pneumatic pressure type
Abstract
The impulse signal producing device comprises a rotatable sleeve
which has several small holes and/or slots, a supply body which is
formed with air ejecting openings at positions inside the rotating
paths of the small holes and/or slots, and a receiving cover which
is formed with output ports at positions corresponding to the air
ejecting openings. The slot is extended in the circumferential
direction of the rotatable sleeve, and one end of the slot in the
rotating direction is arranged on the same generating line of the
rotatable sleeve as that including the position of the small hole.
Air ejected from the openings passes through the small hole and
slot of the rotatable sleeve and flows out of the output ports, to
produce output pulses. By varying the length of the slot in the
circumferential direction, the pulse width can be varied. By
varying the arrangement of the small holes and slots, it is
possible to vary the phases of the output pulses or to produce
several pulses at the same time.
Inventors: |
Ishida; Takashi (Ohi,
JA) |
Assignee: |
Mikuni Kogyo Co., Ltd. (Tokyo,
JA)
|
Family
ID: |
24106465 |
Appl.
No.: |
05/528,624 |
Filed: |
December 2, 1974 |
Current U.S.
Class: |
137/624.13;
137/625.47 |
Current CPC
Class: |
F15B
21/125 (20130101); F15C 3/16 (20130101); Y10T
137/86871 (20150401); Y10T 137/86405 (20150401) |
Current International
Class: |
F15C
3/00 (20060101); F15B 21/00 (20060101); F15C
3/16 (20060101); F15B 21/12 (20060101); F15C
003/16 () |
Field of
Search: |
;137/624.13,624.15,624.18,624.2,625.47,83,624.14,625.11 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Cohan; Alan
Attorney, Agent or Firm: Andrus, Sceales, Starke &
Sawall
Claims
What I claim is:
1. An impulse signal producing device of the pneumatic pressure
type comprising:
a receiving cover,
a pressure cover having an air supply port at its central part and
mounted opposite to said receiving cover,
a shaft rotatably supported in said receiving cover and having an
end,
a rotatable sleeve mounted on said shaft and shaped so as to define
an open end,
a supply body interposed between said receiving cover and said
pressure cover and having at least two openings on its
circumference, said supply body having a section in the shape of a
hat and with a concave central part thereof and mounted on said end
of said shaft with a small diameter portion covering the end of
said shaft, and said body having said openings in the
circumferential surface of a large diameter portion.
a small hole provided in said sleeve in correspondence with one of
said openings,
a slot provided in said sleeve in correspondence with the other of
said openings in said body and extended in the circumferential
direction of said sleeve from on the same generating line of said
sleeve as passes through said small hole, and output ports formed
in said receiving cover in alignment with rotating paths of said
small hole and said slot.
2. A device as defined in claim 1, wherein said pressure cover and
the supply body define a chamber therebetween.
3. A device as defined in claim 1, wherein said receiving cover has
an air vent arranged to also function as a drip hole.
Description
This invention relates to an impulse signal producing device of the
pneumatic pressure type.
Heretofore, it has been customary to employ pneumatic pressure to
prepare various signal circuits for use as control means. A
fluidics circuit has often been used in a control or measuring
circuit. In some of such cases, it is desired to give fluidics the
output of a shaft to thus generate impulses proportional to the
number of revolutions, and to use them as the input or bias signal
of a control circuit or calculating circuit.
U.S. Pat. No. 3,651,824 discloses an approximate impulse signal
producing device of the pneumatic pressure type comprising a
casing, a rotor supported in said casing and formed on its outer
peripheral surface with a surface inclined with respect to the
direction of rotation of the rotor, a pressure supply duct provided
in said casing for ejecting an air jet under pressure to said
inclined surface of the rotor, a drain provided in said casing in a
position substantially symmetrical to the position of said pressure
supply duct, and an output duct provided in said casing and
disposed substantially midway between said pressure supply duct and
said drain. With such device, however, when it is intended to
derive different sorts of pulses in large numbers, the diameter of
a pulse producing disc becomes large and accordingly the whole
device becomes considerably large. As the disc is thinner, it is
better in the efficiency of transmitting the air flow. In this
respect, when the thickness is made small, the disc undergoes a
large deflection because the pressure on the supply side acts on
the whole area of the disc. In anticipation of the deflection, some
extent of clearance (for example, approximately 1/10mm or greater)
must be provided in the disc rotating section. Due to the provision
of the clearance, the pressure recovery rate at output ports
lowers, and the pulse waveform is not very good. Besides, the
thrust of the drive shaft increases, and the countermeasure need be
taken by providing thrust washers and thrust bearings. When, as
described above, the jet for pulses is supplied in the axial
direction and the output pulses are derived in the same direction,
the pulse producing device has the following disadvantages.
1. The diameter of the whole device becomes large.
2. Since the device is subjected directly to the thrust ascribable
to the supply pressure, the countermeasure is necessary.
3. Unless the supply pressure is raised and simultaneously the air
exhaust through an air vent is increased, pulses of good waveform
cannot be acquired. For this reason, the air consumption is
inevitably large.
4. Vibrational noises are caused by the deflection of the rotary
disc.
According to this invention, at least one small hole or
circumferential slot is provided in the surface of a rotary drum
with one end opened, and the jet of supply air introduced into the
rotary sleeve is ejected in the radial direction of a shaft, so
that output pulses are taken out of output ports at the outer
periphery of the drum. Owing to such construction, when the small
hole and the slot of the rotary sleeve are shifted in arrangement,
pulses having a phase shift can be produced. Further, by providing
the small holes or slots at different positions on a generating
line of the rotary sleeve, several sorts of output pulses can be
easily produced at the same time. When the circumferential lengths
of the slots are made different, the time widths of the pulses
vary. It is desirable that the output ports are usually maintained
under the condition of the atmospheric pressure, and that when they
receive the jet, the pulse output of good waveform is provided. To
this end, a supply body which is provided with openings in
proximity to the inner surface of the rotary sleeve and along the
rotating course of the small hole or slot is built in. Thus, output
pulses of good pressure recovery rate can be produced.
An object of the present invention is to provide a device for
producing output pulses of good pressure recovery rate.
Another object of the present invention is to provide a device for
positively producing by mechanical means approximate impulse wave
forms to be used as trigger signals.
The device of the aforementioned nature according to this invention
permits to produce approximate impulse signals of any width as
desired and to deliver them through an output duct. The invention
is useful in simplifying circuits in various control apparatus,
increasing the dependability of the circuits and reducing the cost
of production thereof.
The foregoing objects and advantages of the present invention,
together with various other objects and advantages thereof which
will become apparent, may be attained with the exemplary embodiment
of the invention illustrated in the accompanying drawings and
described in detail hereinafter.
Referring to the drawings:
FIG. 1 is a longitudinal sectional view of a device embodying the
invention;
FIG. 2 is an elevational sectional view taken along the arrowed
line II -- II of FIG. 1; and
FIG. 3 is an elevational sectional view taken along the arrowed
line III -- III of FIG. 1.
FIG. 1 shows a longitidinal section of a pulse producing mechanism.
A shaft 10 is supported in a housing portion 13 of a receiving
cover 11 through bearings 12, 12. On an end face of the receiving
cover 11, a pressure cover 15 having an air supply port 16 is
mounted through a supply body 14 and by a set screw 17.
A rotary sleeve 20 for producing pulses and with its one end opened
is secured to an end of the shaft 10 by a pin 21. The sleeve 20 is
formed at axially different positions with apertures having
different lengths in the circumferential direction thereof, that
is, a small hole 22 and a slot 23. At those positons of the
receiving cover 11 which are radially outside and close to the
small holw 22 and the slot 23, air flow receiving ports or output
ports 18 and 19 are oppositely provided. In the illustrated
embodiment, the small hole 22 is provided at a position of the
rotary drum 20 nearer to the housing 13, while the slot 23
extending in the circumferential direction is provided at a
position nearer to the supply body 14. Since one end of the slot 23
and the small hole 22 are located on an identical generating line
of the sleeve 20 (refer to FIGS. 2 and 3), output pulses have no
phase shift.
As shown in the figures, the supply body 14 has such sectional form
that it is substantially in contact with the inner wall of the
sleeve 20. It is provided with openings 28 and 29 of predetermined
size at positions corresponding to the small hole 22 and the slot
23 of the sleeve 20. A chamber 25 is defined between the supply
body 14 and the pressure cover 15. An air vent 27 serving also as a
drip hole is provided at a corner part of the receiving cover 11
receiving the rotary drum 20.
The exemplary embodiment is the device in which the small hole and
the slot are provided at the axially different positions of the
rotary drum and which can produce the in-phase pulses of different
pulse widths. Of course, when one series of pulses are to be
produced, one small hole or slot may be provided in the rotary
drum. Further, when several series of pulses are to be produced,
several small holes and/or slots may be provided with or without a
phase shift or phase shifts.
In the foregoing device, an air jet is fed from the air supply port
16. Only when, owing to the rotation of the rotary sleeve 20, the
air from the openings 28 and 29 of the supply body 14 passes
through the small hole 22 and the slot 23 being the apertures of
the rotary sleeve 20, it flows into the output ports 18 and 19.
Then, the output pulses are produced. Since, in this manner, the
air flow fed from the air supply port is ejected in the radial
direction of the sleeve, the clearance between the sleeve 20 and
the supply body 14 can be made small. The same applies to the
clearance between the receiving cover 11 and the rotary sleeve 20.
In consequence, air leaking from the supply body 14 and exerting a
thrust load on the sleeve 20 is very slight. The thrust is almost
negligible. Since the respective clearances are small, the pressure
recovery rate of the pulses is good, waveforms as expected are
obtainable, and the air consumption is small.
The advantages of this invention are listed below.
1. Even where a large number of series of output pulses are
required, only the axial length may be made large without
increasing the diameter.
2. In fabricating the rotary sleeve, its diameter can be finished
at high precision by lathe working etc. The clearance between the
rotary sleeve and the air supply body can therefore be set to be
very small (for example, about 3/100 - 5/100mm). Consequently, the
acial thrust arises only slightly, and no special measure against
the thrust is necessary.
3. Owing to the advantage of the preceding item, good waveforms of
the output pulses are achieved. Simultanously therewith, the
pressure of the supply air can be set to be low, so that a
comparatively small air consumption suffices.
4. Since no thrust acts on the rotary sleeve, no vibration occurs
in the axial direction, and almost no noise arises.
* * * * *